Corrosion preventing agent



Patented Jan. 19, 1954 CORROSION PREVENTING AGENT Leo V. Mullen, Jr., Clifton, and James M. Boyle,

Bayonne, N. J., assignors to Standard Oil Development Company, a corporation of Delaware No Drawing.

16 Claims. i The present invention relates to the improvementof hydrocarbon oil products, especially those derived from petroleum sources, and more particularly to the preparation of improved mineral lubricating oil compositions by the incorporation therein of a new class of additives which impart improved properties to such oils and compositions containing them.

In the development of petroleum lubricating oils the trend has been to use more and more efiicient refining methods in order to reduce the tendency of the oils to form carbon and deposits of solid matter or sludge. While such highly refined oils possess many advantages, their resistance to oxidation, particularly under conditions of severe service, is generally decreased and they are more prone to form soluble acidic oxidation products which are corrosive. They are general- 1y less eiiective than the untreated oils in protecting the metal surfaces which they contact against rusting and corrosion due to oxygen and moisture. Although generally superior to lightly refined oils they may deposit films of varnish on hot metal surfaces, such as the pistons of internal combustion engines, under very evere engine'operating conditions.

In accordance with the present invention a new class of substances has been discovered which when added to refined lubricating oils and other petroleum 'oil products in small proportions substantially reduce the tendency of such oils to corrode metal surfaces and which are particularly efiective in inhibiting the corrosion of copper-lead and cadmium-silver bearings.

, The new class of materials which have been found to. possess the stabilizing and detergent qualities described above are reaction products obtained by first reacting an unsaturated dialiphatic hydrocarbon-substituted cyanamide with a primary or secondary aliphatic or cycloaliphatic amine and subsequently sulfurizing the product thus formed with elemental surfur, or other agents which introduce sulfur into the unsaturated aliphatic groups, until from 10 to 30% c'isulfur has been combined therewith. In the reaction between the cyanamide and the amine the reactants are employed in substantially equimolar amounts and the reaction normally takes place within the temperature range of about 100 to about 250 C. The reaction is substantially complete within a period of 1 to 10 hours. In, the sulfurizing reaction flowers of sulfur are usually employed and the reaction takes place at 80-15Q C. within a period of about 1 to 4' hours.

Application December 1, 1950, Serial No. 198,763

It is possible that the above described reaction between a dialkyl cyanamide and an amine takes place in accordance with the equation:

where R and R are aliphatic hydrocarbon groups of the cyanamide, at least one of which is unsaturated and R" is the hydrocarbon group of the amine. The above is merely a suggested equation, since the exact constitution of the reaction product is not known with certainty.

The unsaturated disubstituted cyanamide em.- ployed in the above described reaction may be any cyanamide containing one or more double or triple bonds in at least one aliphatic group, and such aliphatic groups may contain from 1 to 30 carbon atoms each. The aliphatic groups may be straight or branched and may containsubstituent halogen atoms. Examples of suitable disubstituted cyanamides are diallyl cyanamide, methyl allyl cyanamide, dioleyl cyanamide, dilinoleyl cyanamide, di-i-propenyloctyl cyanamide,

and di n octadecenyl cyanamide.

The aliphatic or cycloaliphatic amines whichmay be employed in the above reaction may be any primary or secondary, saturated or unsaturated amine containing from 1 to 30 carbon atoms. Examples of such amines are methylamine, ethylamine, isopropylamine, n-hexylamine, n-octylamine, Z-ethylhexylamine, Lorol amine (a derivative of coconut oil acids consisting of a mixture of C1 to 018 primary aliphatic amines), Armeen 14D (a composition consisting chiefly of n-tetradecylamine with small quantities of ndodecylamine, n-hexadecylamine, and an octadecenylamine),- dimethylamine, diethylamine,

dicetylamine, cyclohexylamine, and dicyclohexyl-- amine.

The preferred compositions of the present invention are obtained by reacting a disubstituted cyanamide with an amine in accordance with.

the method described above and sulfurizing the product with elemental sulfur. However, other products of similar nature and having corrosion inhibiting and antioxidant properties may be prepared by reacting the cyanamide-amine product with a sulfur chloride or bromide to introduce both sulfur and a halogen into the product, and. further reacting this product with an alkali metal is removed as an alkali metal halide and the mercaptide, xanthate, thiocarbamatejj thiophosphate, or phenate, .whe'reby the halogen joined to the molesion be used. For commercialpurposes, it is convenient to prepare concentrated oil solutions in which the amount of additive in the composition ranges from 25 to 50% by weight and to transport and store them in such form. In preparinga lubricating oil composition for use as a crankcase lubricant, the concentrate .will be prepared. from a, lubricating base oil and will beblended with additional quantities of the base oil .as and when required.

The preparation-and testing of an example of the new additives of the present invention are illustrated by the examples to be described in detail below, but it is to be understood that this preparation is illustrative only and is not intended to limit the scope of the invention in any manner.

Example 1.-Preparation of additive (a) g. (0.16 mol')' of diallyl cyanamide was added dropwiseto 37.5 g. (0.17 mol) of molten Armeen 14D, and the resulting solution was refluxed at 210 C. for 6 hours. The reaction mixture was cooled and filtered, and the resulting orange-red oily liquid was found to have the following composition:

Per cent Nitrogen 10.91 Carbon 75.74 Hydrogen 12.65

(b) To 32 g. of the reaction product prepared above was added 12 g. of flowers of sulfur. The resulting mixture was heated at 100 C. for 3 hours and the productwas filtered through Hi-Flo (a filter-aid). The product had the following composition:

Per cent Sulfur 19.78 Nitrogen 9.28

Example 2.-Laboratory bearing corrosion test A blend containing 0.25% by weight of the product'of Example 1 in a paraffinic type mineral lubricating oil of SAE: 20 grade and a-sample of the unblended base oil were submitted to a corrosion test designed to measure the effectiveness Armeen 14D has the following composition:

Per xceni: n-Dodecylamine L n-Tetradecylamine 90 n-He'xa'fiecyiamine 4- Octudecylamine 2 ture was maintained at 325 F. during the test. Two quarter sections of automotive bearings of copper-lead alloy of known weight having a total area of 25 sq. cm. were attached to opposite sides of a stainless steel rod which was then immersed in the test oil and rotated at 600 R. P. M., thus providing sufiicient agitation of the sample during the test. Air was then blown through the oil at the rate of 2 cu. ft. per hour. At the end of each 4-hour period the bearings were removed,

washed with naphtha, and weighed to determine the amount of loss by corrosion. The bearings were .then repolished (to increase the severity of the test) reweighed, and then subjected to the test for additional 4-hour periods in like manner. The results are given in the following table as corrosion life, which indicates the number of hours required for the bearings to lose mg. in weight, determined by interpolation of the data obtained in the various periods.

Bearing Oil or OilBlend Corrosion Lite (His) Base 011 10 Base oil +0.25% product of Example 1 25 Example 3.Lauson engine test Bearing Weight 'Loss (gun/- bearing) Lubricant the like.

The products of the present inventionzmay be employed not only in ordinary hydrocarbon lubricating oils but also in the heavy duty type of lubricating oils which have been compounded with such detergent type additives as metal soaps, metal petroleum sulfonates, metal phenates, metal alcoholates, metal alkyl phenol sulfides, metal organo phosphates, pjhosphites, thicphosphates, and thiophosphites, metal .xanthates.

and thioxanthatesj metal 1 thiocarbamates. and.

have been carefully removed. The oils may be.

refined by conventional methods using acid, alkali and/or clay or other agents suchas ,alu-

minum chloride, or they may be extracted oilsproduced by solvent extraction. with j solvents such as-phenol, sulfur. dioxide-etc. Hydrogenated oils or white oils may be employed as-well.

other types of additives, such. as.

as synthetic oils resembling petroleum oils, prepared, for example, by the polymerization of olefins or by the reaction of oxides of carbon with hydrogen or by the hydrogenation of coal or its products.

For the best results the base stock chosen should normally be an oil which with the new additive present gives the optimum performance in the service contemplated. However, since one advantage of the additives is that their use also makes feasible the employment of less satisfactory mineral oils, no strict rule can be laid down for the choice of the base stock. The additives are normally sufliciently soluble in the base stock, but in some cases auxiliary solvent agents may be used. The lubricating oils will usually range from about 40 to 150 seconds (Saybolt) viscosity at 210 F. The viscosity index may range from to 100 or even higher.

Other agents than those which have been mentioned may be present in the oil composition, such as dyes, pour point depressants, heat thickened fatty oils, sulfurized fatty oils, sludge dispersers, antioxidants, thickener-s, viscosity index improvers, oiliness agents, resins, rubber, olefin polymers, and the like.

Assisting agents which are particularly desirable as plasticizers and defoamers are the higher al ohols having preferably 8-20 carbon atoms, e. g., octyl alcohol, lauryl alcohol, stearyl alcohol, and the like.

In addition to being employed in lubricants, the additives of the present invention may also be used in other hydrocarbon oil products such as motor fuels, heating oils, hydraulic fluids, torque converter fluids, cutting oils, flushing oils, turbine oils, transformer oils, industrial oils, process oils, and the like, and generally as antioxidants in mineral oil products. They may also be used in gear lubricants, greases and other products containing mineral oils as ingredients.

What is claimed is:

1. A hydrocarbon oil containing a corrosion inhibiting amount of a product obtained by reacting together substantially equimolar amounts of a dialiphatic hydrocarbon substituted cyanamide, containing 1 to 30 carbon atoms in each aliphatic group and containing at least one unsaturated grouping in at least one of such aliphatic groups, and an amine selected from the the group consisting of primary and secondary aliphatic and cycloaliphatic amines containing 1 to 30 carbon atoms at a temperature of 100- 250 0., and sulfurizing such reaction product by reacting the same with elemental sulfur until 10 to 30% of sulfur is combined therewith.

2. A composition according to claim 1 in which the hydrocarbon oil is a mineral lubricating oil.

3. A composition according to claim 2 in which the disubstituted cyanamide contains one olefinic grouping in each aliphatic group and in which the amine is a primary aliphatic amine.

4. A composition according to claim 3 in which the disubstituted cyanamide is diallyl cyanamide.

5. A composition according to claim 4 in which the amine is essentially a primary aliphatic amine containing 12 to 18 carbon atoms.

6. A composition according to claim 5 containing approximately 20% of sulfur.

7. A composition consisting essentially of a mineral lubricating oil and the additive as defined in claim 1, the amount of said additive in the composition being 25 to 50% by weight.

8. A composition consisting essentially of a mineral lubricating oil and an additive as defined in claim 6, the amount of said additive in the composition being 25 to 50% by weight.

9. As a new composition of matter a product obtained by reacting together substantially equimolar amounts of a dialiphatic hydrocarbon-substituted cyanamide, containing 1 to 30 carbon atoms in each aliphatic group and containing at least one unsaturated grouping in at least one of such aliphatic groups, and an amine selected from the group consisting of primary and secondary aliphatic and cycloaliphatic amines containing 1 to 30 carbon atoms at a temperature of 100-250 (3., and sulfurizing such reaction product by reacting the same with elemental sulfur until 10 to 30% of sulfur is combined therewith.

10. A composition according to claim 9 in which the disubstituted cyanamide contains one olefinic group in each aliphatic group and in which the amine is a primary aliphatic amine.

11. A composition according to claim 9 in which the disubstituted cyanamide is diallyl cyanamide and in which the amine is a primary aliphatic amine containing 12 to 18 carbon atoms.

12. A composition according to claim 11 containing approximately 20% of sulfur.

13. The process which comprises reacting together substantially equimolar amounts of an unsaturated, dialiphatic hydrocarbon-substituted cyanamide containing 1 to 30 carbon atoms in each aliphatic group and an amine selected from the group consisting of primary and secondary aliphatic and cyclo'aliphatic amines containing 1 to 30 carbon atoms at a temperature of 100-250 C., and sulfurizing such reaction product by reacting the same with elemental sulfur until 10 to 30% of sulfur is combined therewith.

14. A process according to claim 13 in which the disubstituted cyanamide contains one olefinic group in each aliphatic group, in which the amine is a primary aliphatic amine, and in which the sulfurizing step takes place at a temperature of to 150 F.

15. A process according to claim 14 in which the disubstituted cyanamide is diallyl cyanamide, in which the amine is a primary aliphatic amine containing 12 to 18 carbon atoms, and in which the sulfurizing step is continued until 20% by weight of sulfur is combined with the reaction product.

16. The process which comprises refluxing a mixture of substantially equimolar amounts of diallyl cyanamide and a mixture of primary aliphatic amines containing 12 to 18 carbon atoms at a temperature of about 210 C. for a period of about 6 hours, and heating the resulting reac tion product with elemental sulfur at about C. for a period of about 3 hours.

LEO V. MULLEN, JR. JAMES M. BGYLE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,766,755 Lecher et al June 24, 1930 ,464 Loane et al. July 30, 194.0 2,263,562 Bigelow et al. Nov. 25, 19 11 2,325, 86 Bolton et al. Aug. 3, 1%3 2,425,341 Paden et al. Aug. 12, 1947 ,542, 82 Bartleson et al. Feb. 27, 1951 OTHER REFERENCES Zeile et al.: Zeitschrift Physiol. Chem., vol. 

1. A HYDROCARBON OIL CONTAINING A CORROSION INHIBITING AMOUNT OF A PRODUCT OBTAINED BY REACTING TOGETHER SUBSTANTIALLY EQUIMOLAR AMOUNTS OF A DIALIPHATIC HYDROCARBON SUBSTITUTED CYANAMIDE, CONTAINING 1 TO 30 CARBON ATOMS IN EACH ALIPHATIC GROUP AND CONTAINING AT LEAST ONE UNSATURATED GROUPING IN AT LEAST ONE OF SUCH ALIPHATIC GROUPS, AND AN AMINE SELECTED FROM THE THE GROUP CONSISTING OF PRIMARY AND SECONDARY ALIPHATIC AND CYCLOALIPHATIC AMINES CONTAINING 1 TO 30 CARBON ATOMS AT A TEMPERATURE OF 100250* C., AND SULFURIZING SUCH REACTION PRODUCT BY REACTING THE SAME WITH ELEMENTAL SULFUR UNTIL 10 TO 30% OF SULFUR IS COMBINED THEREWITH. 